Tillieux has previously held leadership positions at SBS Broadcasting Europe, Canal+, RTL Netherlands and TF1 in France. He was chief operating officer at media company ProSiebenSat1, but has most recently acted as a business adviser to private equity firms.
He will now be responsible for all management and direction of Red Bee Media's business in Europe and worldwide, leading a team of more than 1,500 employees from the firm's London base. He will take a seat on the board and report to chairman Michael Cook.
Red Bee Media, formed in 2005 from parts of BBC Broadcast, now transmits more than 120 television channels and streams on analogue, digital terrestrial, satellite, cable, web and mobile, including all the BBC domestic networks.
The company has also expanded into digital media, including the creation of a white label video on-demand service and interactive TV guide apps on iPad.
Tillieux said that Red Bee Media is a "true leader" in media services.
"Red Bee Media is a great company, highly respected by today's media clients and well geared up to support the media industry of tomorrow.
"I am excited by this opportunity and I look forward to joining Red Bee Media and leading its teams. It is my intention to focus on further enhancing our services, embracing new technologies and expanding into new markets."
Red Bee chairman Cook said that Tillieux's experience will be vital as the company looks to capitalise on the growing convergence of TV and internet broadcasting.
"His extensive knowledge and experience of the global media industry will be an invaluable asset as we seek out new opportunities for expansion and help our clients to maximise the opportunities afforded by the collision of broadcasting and broadband," he said.
"We are delighted to have Patrick on board and believe that he is the ideal candidate to lead Red Bee Media into the next phase of its growth and ensure that the company remains at the very forefront of media technology, creativity and innovation."
Tillieux joins Red Bee Media as replacement for Bill Patrizio, who stepped down last month after three and a half years with the firm.